ACTG 320 - The primary objectives of the protocol are to determine the clinical efficacy of adding IDV to ZDV and 3TC(TM), compared to the combination of ZDV and 3TC(TM) as measured by the time to an AIDS- defining endpoint or death. Subjects will re-ceive open-label IDV if they reach a defined study endpoint (i.e. a new AIDS-defining illness) and can have their ZDV changed to d4T if they become intolerant to ZDV after the first 24 weeks of the study.